1. Field of the Invention
The present invention relates generally to improved, highly light sensitive semiconductor devices and more particulary to a solid-state charge-coupled photoconductor having electronically controlled photosensivity.
2. Description of the Prior Art
Solid-state photodiode detectors are known and used for image detection such as pattern recognition, position sensing, image tracking, and many other applications.
For example, U.S. Pat. No. 3,812,518 entitled "Photodiode With Patterned Structure", issued May 21, 1974 to Kury et al and assigned to General Electric Company discloses a semiconductor photodiode having buried elongated strips of p-type diffusion regions to collect electron-hole pairs produced by a light sensitive surface n-layer. Elongated p-type strips are used to reduce the device capacitance and increase sensitivity.
U.S. Pat. No. 3,816,769 entitled "Method and Circuit Element for the Selective Charging of a Semiconductor Diffusion Region", issued June 11, 1974 to Crowle and assigned to integrated Photomatrix Ltd. also discloses a photosensitive detector including a first type substrate, an opposite type diffusion region and a gate region.
Further U.S. patents characteristic of the state of the art include U.S. Pat. No. 3,795,805 entitled "Method and Apparatus for Sensing Radiationand Providing Electrical Readout", issued Mar. 5, 1974 to Eichelberger and assigned to General Electric Company; U.S. Pat. No. 3,808,476 entitled "Charge Pump Photodetector", issued Apr. 30, l974 to McCann, Jr. and assigned to Westinghouse Electric Corporation; and U.S. Pat. No. 3,814,955 entitled "Charge Coupled Semiconductor Element with Noise Cancellation", issued June 4, 1974 to Itok et al and assigned to Hitachi, Ltd.
The publication entitled "Photosensitivity and Scanning of Silicon Image Detector Arrays" by Savvas G. Chamberlin, IEEE Journal of Solid State Circuits, Vol SC-4, No. 6, December 1969 discusses basic principles of operation of planar Si p+- n photodiodes for image scanning and is useful as a background teaching in the understanding of the present invention.